I was reading the biography of a 14th century Magadhan Buddhist monk (Sunyaadis'ya) who traveled all over India, Lanka, China and Korea before finally settling in Korea. The interesting thing is that he had studied and ordained in the famous Nalanda university, which was the center of Mahayana Buddhism in middle India at that, but he was sent by his professors to Sri Lanka to meet a famous master their to be able to understand the meaning of Prajna. This he did, and after spending 6 months in a cave in Ceylon, he finally understood the meaning of Prajna which that master had asked him to find.

Both Vajrabodhi and his disciple Amoghavajra also traveled to Sri Lanka to learn and collect Tantric manuals (Mahavairocama sutra especially). So it appears that despite the present reputation of Sri Lanka as a Theravada center, Sri Lanka was well known in medieval and ancient history as a prominent location for Mahayana and Vajrayana Buddhism. Not to mention, even the Lankavatara Sutra is supposed to have been delivered in Sri Lanka.

How and why did Mahayana/Vajrayana become completely extinct in Sri Lanka?

Rakshasa wrote:I was reading the biography of a 14th century Magadhan Buddhist monk (Sunyaadis'ya) who traveled all over India, Lanka, China and Korea before finally settling in Korea. The interesting thing is that he had studied and ordained in the famous Nalanda university, which was the center of Mahayana Buddhism in middle India at that, but he was sent by his professors to Sri Lanka to meet a famous master their to be able to understand the meaning of Prajna. This he did, and after spending 6 months in a cave in Ceylon, he finally understood the meaning of Prajna which that master had asked him to find.

Both Vajrabodhi and his disciple Amoghavajra also traveled to Sri Lanka to learn and collect Tantric manuals (Mahavairocama sutra especially). So it appears that despite the present reputation of Sri Lanka as a Theravada center, Sri Lanka was well known in medieval and ancient history as a prominent location for Mahayana and Vajrayana Buddhism. Not to mention, even the Lankavatara Sutra is supposed to have been delivered in Sri Lanka.

How and why did Mahayana/Vajrayana become completely extinct in Sri Lanka?

There is some info on this in "A Search for Mahayana in Sri Lanka," by Mahinda Deegalle, JIABS 22 (2) 1999

There is also a good recent dissertation about Śūnyādiśya/Dhyānabhadra/Zhikong that is probably of interest. It's called ‘THE LAST LIGHT OF INDIAN BUDDHISM’ - THE MONK ZHIKONG IN 14TH CENTURY CHINA AND KOREA by Ronald James Dziwenka.

Hwa an sa temple. ji-kong(Zhi kong)'s sari stupa is here. at the last a few years he went to Yan jing(Bei jing) and lived Fa yuan si temple where build by Korean, after he passed away, his sariras were brought to Korea in 1370 and preserved in a stupa in Hwa am sa temple. http://blog.daum.net/ds5rwi/9967124